Leapfrog Didj: Handheld Linux on the Cheap

Today our good friends over at Woot! are selling the Leapfrog Didj, a low cost educational toy aimed at little kids. Lucky for hackers out there, the Didj is actually a linux device, and gaining serial console access is as easy as soldering two wires. The documentation out there is a little outdated, with a number of broken links and stale wikis, but $25 for a portable linux device is a hard deal to beat. A list of sites which might be helpful are listed after the break, as well as the hardware specs of the Didj.

Let us know if you have played around with hacking the Didj before, and if you have any tips for other readers. Don’t forget to tell us what you do with the Didj as well!

it also looks like what little scene there was died 2 years ago, and the most progress that was made was hooking up the serial port so you can poke around in its underbelly

If there was a active scene, with more progress and maybe even a sdk I would jump all over this, but with a 2 year old dead scene, and nothing much else besides ssh-ing into it, I have to pass, it really doesnt seem worth the effort

The GP2X is far more hackable has a SDK. This half hacked toy is not worth the effort unless you have days of time in mom’s basement to get to where you can be in 30 seconds on one of the open linux handheld gaming platforms.

* Get the v1.2 tarbal from http://www.cabextract.org.uk/
* extract it
* run ./configure
* run make
* copy the bin somewhere convienent like /usr/local/bin
* cabextract -d test DidjPlugin.exe will put all the extracted files in the test directory.

The .lfs files are really .zip files inside

Mount the rootfs.jffs2 somewhere convinent and do a ls -lR >files this will give you a list of what’s inside.

Hack away!!

BTW here is how to mount the rootfs.jffs2 image onto the temp directory:

+1 for “cool, I wish I had something to use it for”. No built-in wireless, so I can’t have it “control” anything; no commodity memory slot, so I can’t have it read/play/view any sort of media. No analog input / touchscreen, so your input vocabulary is pretty limited. I *want* to want to hack one of these, but I come up with anything that sounds like a good idea.

Just a heads up to those that ordered from woot and have not experienced their shipping yet. Usually you would get your item in about 1.5-2 weeks but they just had a long woot-off and so they may be slightly behind on shipping so it may take about 3 weeks till you get your goods just so you know unless you 2 dayed it.

Looks like Claude Schwartzs Gerbers could be run at BATCH PCB and get Me a set of SD cartridges for hacking. I got two didj’s from woot. So by the time they arrive from snail mail. I can have the batch PCB’s here as well.

@daveland
Sure , the gerbers should work at any PCB manufacture. No fancy drill sizes or line widths are used. But the FT232R footprint is not easy to solder by hand.

@emu
I already ported over a library (libcastor from Orkie)from the GPH Wiz which handles graphics and input. So emulators are doable , most of the stuff which runs on the GPH Wiz *should* work on the Didj as well.

omg, i missed it. if anyone has ordered a spare one just for the sake of it, or has second thoughts about the order.. please let me know at illlion@gmx.com, id love to hack around with one of these. im sure we can arrange something.

For those of you who want a linux handheld but maybe something with a bit better community, check out the zipit wireless messenger (version 2). It’s like $50, has an SD card slot, and wifi. And I think already has emulators ported.

Just to let people know we have a active wiki going at: http://www.elinux.org/Didj
I have posted an eagle library for the cartridge pins and have posted a eagle board file that works as a breakout board.

@hpux735
I just made a breakout board I didnt use the FTDI chip mainly because I needed a quick breakout board and the final board wont even need a usb it will hopefully just need a microsd.

@Robert
It cant play roms yet but that is one of the goals of the project.

@PinkFreud
The diji already has a usb slot and if you know what your doing you can get to some of the internal storage with it. The wiki has some instructions on this.

Great! This is exactly what I need to get started! I tried to massage the Altium Designer stuff into eagle with no avail. With the eagle library we all can just make whatever cartridge we need! I’ll probably start with a SD (maybe micro) and USB serial. Eventually I may look into putting a RF transciever (Like the Micrel MICRF600 series), high-density flash for the OS, and SD for datalogging.

Take a look at that cartridge I made because its really easy to make the cartridge lock in like the real one. My goal is to make the pcb like 5mm inside the slot then I am going to sand down a block of plastic and super glue it on the edge of the pcb inside the diji then when the cartridge is in the digi it will look like a real cartridge. I am going to do this with a microSD inside because one we get everything working we shouldn’t need the serial anymore.